Hysteroscopic Fluid Media and Complications
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Direct answer
Hysteroscopic distension media are fluids that open the uterine cavity so that it can be seen and operated on, and the choice of fluid must match the energy source. Non-electrolyte solutions such as glycine 1.5% and sorbitol-mannitol suit monopolar resection, whereas normal saline suits bipolar devices. The most serious complication is fluid overload with hyponatraemia, known as TUR syndrome, which is prevented by tracking the fluid deficit.
What you must remember
- Normal saline: an isotonic electrolyte solution used with bipolar energy, which avoids dilutional hyponatraemia but can still cause fluid overload if large volumes are absorbed.
- Glycine 1.5%: a hypotonic non-electrolyte medium used with monopolar energy, with risks of hyponatraemia and hyperammonaemia from its metabolism.
- Sorbitol-mannitol: a hypotonic non-electrolyte mixture used with monopolar energy, where sorbitol metabolism calls for caution in liver disease and diabetes.
- Energy match: electrolyte solutions conduct and disperse monopolar current, so non-electrolyte media are needed for monopolar resection.
- Fluid deficit: the volume infused minus the volume recovered from suction, drapes and pads; a deficit above about 1 litre with hypotonic media (about 2.5 litres with saline) is a commonly used warning threshold.
- TUR syndrome: hyponatraemia, hypo-osmolality and fluid overload cause nausea, confusion, visual disturbance, hypertension and bradycardia, and in severe cases pulmonary oedema and seizures.
- Management: stop the procedure, give oxygen and diuretics, check serum sodium urgently, and correct it slowly to avoid osmotic demyelination.
Matching the medium to the energy and the risk
The distension medium is chosen before the procedure starts, because it must suit the energy source and the expected volume of the case. A brief diagnostic examination absorbs little fluid, whereas operative work such as hysteroscopic myomectomy can absorb a large volume. The table lists the common options and the complication that each one carries.
| Medium | Tonicity | Energy used | Key risk |
|---|---|---|---|
| Normal saline 0.9% | Isotonic | Bipolar | Fluid overload if volume is large |
| Glycine 1.5% | Hypotonic | Monopolar | Hyponatraemia and hyperammonaemia |
| Sorbitol-mannitol | Hypotonic | Monopolar | Hyponatraemia, with metabolic caution in liver disease |
| Carbon dioxide gas | Not applicable | Diagnostic only | Gas embolism, which is rare |
Every hypotonic medium carries a risk of dilutional hyponatraemia, so fluid balance must be tracked throughout the case. A small deficit in a short diagnostic procedure rarely matters, whereas a long resection may need a planned upper limit on the volume infused. The anaesthetist should be told which fluid is in use, because the sodium and volume effects can persist after the operation ends.
Where the exam tries to catch you
Questions here test the match between fluid and energy, and what to do when TUR syndrome appears.
- Trap: Choosing saline for a monopolar resection. Correct: Conductive electrolyte solutions disperse monopolar current, which makes the resection ineffective, so non-electrolyte media are used.
- Trap: Correcting hyponatraemia rapidly to restore sodium quickly. Correct: Rapid correction risks osmotic demyelination, so the rise in serum sodium must be slow and monitored.
- Trap: Ignoring fluid balance because the case looks short. Correct: The deficit accumulates through the procedure, so infused and recovered volumes must be recorded continuously.
- Trap: Continuing the resection while the patient develops confusion or visual change. Correct: Stopping the procedure is the first step in TUR syndrome, followed by oxygen, diuretics and sodium checks.
Frequently asked questions
Why is normal saline not used for monopolar hysteroscopic resection?
Normal saline is an electrolyte solution, which conducts current and disperses monopolar energy. This makes monopolar cutting ineffective. Non-electrolyte media such as glycine or sorbitol-mannitol are therefore used with monopolar devices, while bipolar systems are compatible with saline.
What is TUR syndrome in hysteroscopy?
TUR syndrome is a combination of hyponatraemia, hypo-osmolality and fluid overload caused by absorption of hypotonic irrigating fluid. It presents with nausea, confusion, visual disturbance, hypertension and bradycardia. In severe cases it can cause pulmonary oedema and seizures.
How is fluid deficit calculated during hysteroscopy?
Fluid deficit is the volume of distension fluid infused minus the volume recovered from suction, drapes and pads. The team should track it throughout the procedure. A deficit above about 1 litre with hypotonic media, and about 2.5 litres with saline, is a commonly used warning threshold, although units differ in their limits.
How should hyponatraemia from hysteroscopic fluid be treated?
The procedure should be stopped, oxygen given and diuretics considered, with serum sodium checked urgently. Severe hyponatraemia with seizures may need hypertonic saline. Sodium must be corrected slowly, typically no more than about 8 to 10 mmol/L in 24 hours, to avoid osmotic demyelination.